The proposed research is an investigation of visual depth perception in infancy. Though we know that young infants are sensitive to cues that are associated with depth, this does not necessarily mean that these infants perceive spatial depth. In order to infer that an infant is perceiving depth, paradigms employing a response appropriate to spatial relations or response transfer across depth cues must be observed. In the present study, two- and four-month-old infants will participate in a transfer across depth cue paradigm. Subjects' visual attention to two stimuli will be habituated. During these trials, both stimuli will undergo the same change in depth (e.g., approach toward the subject) as specified by the same cue to depth (e.g., retinal disparity). Habituation trials will continue until a response decrement of 50% of the maximal fixation response level has been reached. Once the habitiation criterion has been met the test trials will begin. These will consist of one approaching and one withdrawing stimulus, each specified by the cue to depth which was not used during the subject's habituation trials (e.g., optical expansion/contraction). If the infants demonstrate a fixation preference for the stimulus for which the direction of motion in depth has changed, depth perception will be inferred.